The inventio relates to a more uniform feeding of fibrous material from a chute to a carding or like machine in the form of a fiber batt. Various forms of chute feeds have been heretofore provided which typically include a vertical chute having a reserve section and lower formation section. A top feed roll and fiber opening roll are disposed above the chute of the formation section for supplying opened fibrous material from the reserve section. A pair of bottom delivery rolls discharge the fibrous material in the form of a compacted batt.
The top feed roll feeds to the opening roller the fibers which have, to some extent, been previously opened and individualized. The further separated and opened fibers are then deposited into the formation section. In the formation section, an oscillating compacting plate compresses and compacts the fibers to increase and make more uniform the bulk density of the fibers prior to entering the nip of the bottom delivery rolls. By controlling the speed and degree of movement of the oscillating plate the bulk density and volume of the fibrous batt can be prescribed. The performance of the compactor plate depends, in part, on the degree and uniformity of compaction of the fibers in the formation section.
In the reserve section, the formation of a reserve of fibers which are supplied at a uniform weight along the axial length of the feed roll is a problem to which considerable attention need be given. Typically, the fibers are formed in a reserve stack or column above the feed roll. However, the fiber drag produced on the front and rear interior walls of the reserve section can cause the fibers to form a column whose weight is non-uniform along the length of the walls. The feed roll, whose axis is parallel to the front and rear interior walls, receives a non-uniform weight of fibers along its length for feeding to the formation section below the feed roll.
The width of the column of fibers between the front and rear reserve section wall determines its weight. It would be highly desirable to be able to adjust the width of the fiber column and thus prescribe the weight of the column of fibers being fed by the feed roll to meet the needs of the application and type of fiber being fed. At the same time, feeding of the prescribed column without drag or other influences affecting the uniformity of the column is necessary.
Another problem in uniformly feeding the fibers has been the non-uniform compaction of fibers in the lower end of the reserve chute. With the fibers unevenly compacted, the feed roll cannot in turn feed the fibers in a uniform manner. Some reserve sections have walls which taper slightly outwards toward the feed roll, and the fibers become compacted in a wedge-shaped column above the feed roll. Often, the walls of the reserve section are perforated or of screen material to allow for the escape of air transporting the fibers. This occurs at a lower portion of the reserve chute which tightly compacts the fibers down against the lower walls.
The non-uniform feeding of fibers, whether from weight variations due to drag, overcompaction, or other factors, results in the feeding of non-uniform fiber tufts into the formation section. Lumps and irregularities result in bulk density variations in the fiber batt discharged from the chute feed.
Accordingly, an object of the present invention is to provide an apparatus and method for more uniformly supplying fibers in a chute feed and accurately prescribing the weight thereof.
Still another object of the present invention is to provide an apparatus and method for supplying fibers in a more uniform column of a prescribed shape in a reserve section of a chute feed for proper feeding of a prescribed weight of fibers to a formation section of the chute feed.
Still another object of the present invention is to provide an apparatus and method for supplying fibers in a fiber column having a predetermined shape which avoids drag against the chute walls and other factors tending to alter the uniform column shape.
Still another object of the present invention is to provide a chute feed having a reserve section with a pair of opposed adjustable sidewall elements which can be adjusted to shape a fiber column in the chute from which fiber is fed to an opening roll.
Yet another object of the present invention is to provide a chute feed in which fibers are supplied in a more uniform column of fibers having a desired width and a level surface along the top thereof for more precise feeding through the chute feed.
Devices which are superficially similar to the invention are those shown in German Patent (Patentschrift) DE 3149965 wherein a pivotal vane is disclosed mounted in a formation chute to vary the width of the fiber batt delivered to a card. U.S. Pat. No. 3,963,111 discloses a cotton gin feeder wherein the shaft or chute of the feeder may be operated as a single chamber or a double chamber by actuating movable side valves to vary feed rate.